Shield for electromagnets



Nov. 7, 1950 R. F. WILLIS SHIELD FOR ELECTROMAGNETS Filed June 3, 1948INVENTOR. RALPH F. WILLIS Y E N R 0 w A ?atented Nov. 7, 1950 UNITEDSTATES PATENT OFFICE SHIELD FOB ELECTROMAGNET S Ralph F. Willis,MeKeesport, Pa., assignor to National Tube Company, a corporation of NewJersey Application June 3, 1948, Serial No. 30,881 2 Claims. (Cl.294-655) to be used under water. However, such magnets areunsatisfactory for applications in which they are subject to severerough handling, such as in cleaning scale pits around steel mills. Roughhandling may damage the water-proof seals and cause leaks that ruin themagnet.

An object of the present invention is to provide improved shields forelectromagnets adapting the magnet to be used in shallow water and beingcapable of withstanding rough handling without developing leaks.

A further object of the invention is to provide improved electromagnetshields which are readily installed or removed from the magnets andwhich substantially conform to the contours of the magnet and do notmaterially affect the lifting characteristics.

A further object of the invention is to provide, in combination with anelectromagnet, an improved shield which protects the magnet for use inshallow water despite rough handling and which does not substantiallyaffect the lifting characteristics.

In accomplishing these and other objects of the invention I haveprovided improved details of structure, a preferred form of which isshown in the accompanying drawing, in which the single figure is avertical sectional view of an electromagnet having an improved shieldembodying features of the present invention.

In the drawing, there is shown at l an electromagnet, which is designedfor lifting and transporting magnetic articles and is suspended from anoverhead crane for this purpose. The suspending means illustratedcomprises a pair of cables l2 and I3 carried by the crane, a yoke l4towhich the cables are attached and which carries'a link l5. Magnet IIIis suspended from link I! by a plurality of chains IS. The magnet isenergized through an electric cable IT. The magnet is encased in a'housing which is not necessarily water-proof and is illustrated ashaving a dished undersurface l8. Such structure is typical ofelectromagnets employed for-lifting purposes, but obviously the shieldof the present invention may be employed with magnets of differentconstruction or having different suspending means.

The shield of the present invention comprises an open top, cylindricalcontainer l9. The inside 2. diameter of the container is such as toreceive magnet ll freely. The height of the shield is greater than thedepth to which the magnet will be submerged so that water does not enterthe container through the open top. Preferably the container is formedin two sections, a bottom section 20 and a top section 2| weldedtogether as at 22. Preferably the upper rim of the container has anannular reinforcing strip 23. The bottom of the container is shaped toconform with the dished underface of magnet l0 so that there is no openspace between the bottom of the magnet and the container.

The shield is suspended from yoke H by a pairof slings 20 and 25 securedto reinforcing strip 23. Preferably slings 24 and 25 contain tensionsprings 26 which draw the container into close engagement with thebottom of the magnet.

In order that the magnet may release articles readily when it isde-energized, the shield is preferably of a material which has onlyslight residual magnetism. The material may be a nonmagnetic materialsuch as bronze, but I find that various steels which have low residualmagnetism are satisfactory.

From the foregoing description it is seen that the present inventionprovides a shield which effectively protects electromagnets from waterand yet is capable of withstanding rough handling without damage. Theshield is readily removable from the magnet when it is not needed. Sincethe shield is fitted closely against the magnet, there is no substantialinterference with the lifting characteristics.

While I have shown and described only a single embodiment of theinvention, it is apparent that modifications may arise. Therefore, I donot wish to be limited by the disclosure set forth but only by the scopeof the appended claims.

I claim:

1. A shield for protecting electromagnets used in shallow watercomprising a cylindrical open top container of material having lowresidual magnetism, said container being adapted to receive freely anelectromagnet, the configuration of the bottom of the containerconforming to that of the bottom of the magnet, slings carried by theupper portion of the container adapted to suspend the container from amagnet suspending means and tension springs in said slings for drawingthe bottom of the container into engagem nt with the magnet.

2. A shield for protecting electromagnets used in shallow watercomprising a cylindrical open top metal container of two-piece weldedconstruc- 2,629,440 3 4 tion and being or metal having low residual mae-REFERENCES CITED netism, said container being adapted to receive freelyan eleotromagnet, the configuration of the g; figii t are of record mthe bottom of the container conforming to that of the bottom of themagnet, a reinforcing strip 5 UNITED STATES PATENTS carried by the upperedge or said container, slings Number Na Date joined to said containerthrough said reinf roinfl 906,599 Ahlm Dec. 15, 1908 strip ada ted tosuspend the container from a 950,718 Eastwood Mar. 1, 1910 magnetsuspending means, and tension springs in 2,239,750 Weeks Apr. 29, 1941said slings Ior drawing the bottom of the con- 0 tainer into engagementwith the magnet. RALPH F. WILLIS.

